A 5-year review of the microbiology of acute complicated bacterial sinusitis at the University of the Witwatersrand

Abstract:

SUMMARY
This study retrospectively analysed the bacteriology of 226 patients who were
admitted, with acute complicated sinusitis, to the University of the
Witwatersrand’s ENT complex over a 5-year period, between the 1st January
2002 and 31st December 2006. There were 159 male and 67 females (ratio
2.4:1) aged between 1 and 74 (mean 16.5 ± 0.7) years. 116 (51.3%) patients
were 15 years and younger and 110 (48.7%) were above the age of 15 years.
All 226 patients had one or more of an orbital, soft tissue or bony
complication and underwent open sinus surgery by way of an external
frontoethmoidectomy approach (or ethmoidectomy) with maxillary sinus
puncture and sinus washout. Intracranial complications were present in 37
(16.4%) patients of whom 12 required drainage of a subdural empyema and,
one required drainage of a brain abscess.
233 microorganisms were isolated for analysis from positive cultures obtained
from 163 (72.1%) patients (1.4 isolates per specimen) and 63 (27.9%) cultures
were negative. Aerobic and facultative anaerobes accounted for 199 (85.4%)
of the isolates whilst anaerobes accounted for 31 (13.3%) and fungi for 3
(1.3%). 107 (65.4%) of the positive culture specimens were monomicrobial
whilst 56 (34.6%) contained 2 to 4 different species of microorganism. The
proportion of anaerobes was notably higher (p<0.05) polymicrobial specimen
than in monomicrobial specimen.The most commonly isolated aerobic microorganisms were Streptococcus
milleri (18.5%), Staphylococcus aureus (12.4%), β-haemolytic streptococci
groups A, C, F, and G (10.3%), coagulase negative staphylococcus (8.6%) and
Haemophilus influenzae (8.6%). In contrast, Streptococcus pneumoniae
(2.6%) and Moraxella catarrhalis (0.4%) were not major pathogens.
Peptostreptococcus (6.4%) and Prevotella (4.7%) species were the most
common anaerobes.
The profile of isolates was not influenced by gender or by the presence of
intracranial complications. However, age and location did have a significant
(p<0.05) impact. Haemophilus influenzae was more significant (p<0.05) in
patients aged 15 years and younger. Streptococcus milleri was the most
common isolate (28.3%) at the Chris Hani Baragwanath Hospital but ranked
5th (2.3%) at the Johannesburg Hospital. β-haemolytic streptococci and
coagulase negative staphylococcus ranked 1st (20.8%) and 2nd (14.8%)
respectively at the Johannesburg Hospital but only 4th (4.8%) and 5th (2.8%)
respectively at the Chris Hani Baragwanath Hospital.
Penicillin, ampicillin and erythromycin were effective against Streptococcus
milleri, β-haemolytic streptococci, Streptococcus pneumoniae and
streptococcal species. Cloxacillin was effective against Staphylococcus aureus
and coagulase negative staphylococci. Methicillin-resistant Staphylococcus
aureus was isolated in 3 patients (1.3%). Haemophilus influenzae was resistant
to ampicillin in 22.2% cases in which it was the sole pathogen.